The study tests the hypothesis that a "controlled" phospholipid surfaceconsisting of a substrate, polydimethylsiloxane polymer and a phosphatidylcholine ester can be assembled by use of sequential grafting chemistries. Olefin functional trihydroxy silanes are reacted with glass or silicon dioxide to provide a self-assembled monolayer of reactive vinyl groups. Gold surfaces and alkane thiols will also be utilized to form a vinyl-rich surface by self-assembly. Afterwards hydride functional polysiloxanes are grafted to the surface vinyl groups using soluble platinum catalysts. Finally, the residual hydride groups on the polysiloxane are reacted again by platinum-catalyzed hydrosylilation of olefin functional phosphatidylcholine esters to create the ultimate blood-contacting layer. At each stage, the surface elemental composition is determined by ESCA and SIMS spectroscopies.